Most satisfying system change in 2017?

Picked up a pair of Klipsch Heresy IIIs..... very much a 180 from my last speakers but very dynamic and fun to listen to....especially with live recordings / concert blurays.   Amazing how great they sound with 40 watts of EL34 power..... hope to build a SET kit soon.

I picked up a very low hour First Watt F5. To my ears,a very,very great amp.

Legacy Audio Whispers w/ Wavelaunch. Love em.

My PS Audio DirectStream memory player.  Paired with my PS Audio DirectStream DAC, the best digital sound I've experienced.

swapping out a Hafler dh100 pre for a Modwright 9.0 swl 
solid state rectified........this has been a tube revelation for me.
Very happy with it.
Also my wife got me Dragonfly Red for Christmas.
Originally to use through a Dell laptop but had some issues there
so tried on my wife's ipad to very good results.
Listen to youtube music mostly at night especially NPR tiny desk
studio which are often excellent and lets me hear many musicians
I would otherwise probably not find. Dragonfly good enough to
keep me coming back for more.